1. Field of the Invention
This invention relates to a recording method and a recording apparatus for recording data transmitted in irregular periods.
2. Description of the Related Art
In contrast to printers which record on the basis of recording data transmitted in regular periods, printers used in facsimile apparatuses or the like have generally had the following problems. In the case of a facsimile apparatus, for example, recording data is generated from received data in periods which vary depending upon the period in which the received data is received or the period in which the received data is decoded, with the result that the recording period for the recording data also varies. This is particularly true in the case of an interval between ECM reception blocks in facsimile reception or in the case of the reception of a half-tone document image. In such cases, the processing of the received data takes a long time, resulting in an extremely long recording time period. The printer section of a facsimile apparatus generally employs a thermal-transfer-type printer, which records by heating the ink of an ink sheet by means of a thermal head to transfer it onto recording paper. Thus, such a long recording period results in a reduction in the temperature of the ink sheet and the thermal head before the recording of the next line, thereby reducing the recording density of the next line. Further, when the recording period is long, the motors for feeding the ink sheet and the recording paper are operated to record the next line after having remained completely at rest, with the result that unevenness is generated in the feeding of the ink sheet and the recording paper, thereby deteriorating the recording quality.
To solve these problems, various measures have been proposed. For example, when the interval between the recording of one line and the formation of recording data for the next line is long, the thermal head is re-heated in accordance with the same data as used in the previous recording without feeding of the recording paper again (post-heating), or the thermal head is heated immediately before the recording of the next line to such a degree as not to cause it to record (pre-heating) (U.S. Pat. No. 4,963,884 and Japanese Patent Laid-Open Publications No. 62-3969 and 58-211473). However, even with such pre-heating or post-heating control, it has been impossible to obtain satisfactory recording quality. In the case of multi-printing, in particular, other problems may arise in addition to the deterioration in the recording quality as mentioned above. In multi-printing, which uses an ink sheet (a multi-print sheet) which permits image recording a plurality of (m) times, recording of a document having a length L is performed by feeding the ink sheet a feed length smaller than the length L (i.e., L/m). In this process, the ink sheet and the recording paper are apt to stick to each other, or an ink trail may be left on the recorded image.
To prevent the deterioration in recording quality mentioned above, a method is known in which a buffer memory for storing a plurality of lines of recording data is provided. This buffer memory compensates for the variation in the recording period of the received data, and the recording data is read from the buffer memory and recorded at uniform speed. However, to compensate for the variation in the period of the recording data and record the same at a completely uniform speed, a considerable memory capacity (e.g., approximately 8M bytes) is required. Apart from this method, another method has been proposed in which a plurality of small-sized buffer memories are provided so as to realize a uniform-speed recording by switching between these memories (U.S. Ser. No. 862,417, filed on Apr. 2, 1992). However, as stated above, data is received in facsimile communication at irregular periods, so that, if, at the time of buffer switching, it takes a long time for the recording data to become ready for recording in the next buffer, the recording operation will be suspended at that time.